1. Field of the Invention
The present invention relates in general to a method and apparatus for removing skins from nuts, and more particularly to a method and apparatus for blanching different sizes of peanuts.
2. Description of the Prior Art
Various prior art devices have been used for blanching nuts. One such prior art device is the nut blanching apparatus shown in U.S. Pat. No. 4,432,275, issued to Zekert et al., the disclosure of which is hereby incorporated by reference. Zekert et al. discloses counter-rotating rollers, between which nuts are passed between two opposing sets of hollow elastic tubular rings moving at slightly different speeds for removing skins from nut meat. Zekert et al. further discloses various other prior art devices for blanching nuts, the disclosure of which is hereby incorporated by reference.
Prior art blanching devices typically apply a combination of pressure and abrasion to remove the skins from nuts. When insufficient pressure is applied to the nuts, more will pass through a nut blanching device without having the skin removed. Application of excessive pressure causes the nuts to split, and thus reduces the yield rate of whole nuts. Excessive abrasion of the nuts creates excessive fines, which are the powdered particulates which result from grinding off a portion of the nut meat from nuts as they are processed. In some cases, excessive pressure acting with excessive abrasion can also split nuts. Whole nuts sell for more than split nuts. Also, nuts are typically sold by weight, so excessive fines reduces the price for a batch of processed nuts.
Additionally, nuts come in various and assorted sizes for particular types of nuts. Wide ranges of sizes for particular types of nuts are typically processed, often requiring excessive component adjustment and changing of components for prior art nut blanching equipment. A high degree of control, with repeatable control parameters and adjustments, is required for blanching nuts over a large range of nut sizes to have a high yield rate. Higher yield rates for blanched whole nuts are obtained by removing the skins from a high percentage of nuts, reducing the amount of fines, and reducing the amount of nuts which are split.